Comments on: First birds were poor fliers – flaps would have buckled Archaeopteryx feathershttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/
Mon, 26 Nov 2012 12:00:51 +0000hourly1http://wordpress.org/?v=4.0.1By: Ed Yonghttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7549
Sat, 22 May 2010 17:46:26 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7549I’m more recounting arguments that others have put forward. My own view is that the animals were unlikely to have been good fliers.
]]>By: Sam Whttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7548
Sat, 22 May 2010 10:09:33 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7548You say that muscles normally attached at the breastbone could also have attached elsewhere. But then they would have to “rewire” to make modern birds where they attach at the breastbone. How likely would this be? I was always taught that “rewiring” of organs is unlikely and too big a step (e.g. larygeal nerve still curves around aorta).
]]>By: Zach Millerhttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7547
Sun, 16 May 2010 00:48:23 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7547@ Joel:

Yes, it sort of destroys it.

]]>By: Joelhttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7546
Fri, 14 May 2010 12:47:19 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7546Also it seems it might provide additional support for the trees-down hypothesis. An inability to flap would surely complicate ground-up takeoffs.
]]>By: Sniffnoyhttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7545
Fri, 14 May 2010 11:25:23 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7545A thought: Does this have any implications for the WAIR hypothesis?
]]>By: Chris M.http://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7544
Fri, 14 May 2010 07:24:08 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7544Huh! I’m a little surprised at your choice of title, but it sounds like the paper takes this tack as well. So let’s compare ancient birds to some of the best fliers in the bird world.

First, pigeons and albatrosses are really remarkably good fliers, and gulls and albatrosses operate in some extremely unforgiving conditions; if they’d chosen birds that don’t deal with as much severe weather or extreme speed (people often just don’t appreciate just how well pigeons fly) you might see very different results, since those are exactly the conditions that are likely to require the high failure margins they point out.

On solid-core, it seems pretty unremarkable to me that feathers may have developed over time to optimize weight-strength ratio. With the higher weight to strength ratio in solid core, the ecological payoff for reducing weight and operating near the failure threshold is a lot greater. You rarely if ever see a modern bird feather broken at the rachis, unless they’ve been in some way crushed, which may indicate that this is not a big problem anymore. Developing hollow-core feathers may have partly removed this constraint, and limited the degree to which you can actually compare the failure criteria.

They also may be underestimating the degree to which flying mechanics can vary load. A good chunk of that high loading at the extremes of the sweep can be avoided with a number of small changes, such as having larger wing area (as I’ve generally seen Archaeopteryx illustrated) and a slightly less efficient, but safer, flap, with lower peak accelerations. Again, a trade-off that results in slightly lower performance, but not a lot.

Another important point is that the bending failure of a hollow structure versus a solid one is very different; I’d have to read the paper to see what exactly how they quantified buckling, but solid-core materials approach failure gracefully, rather than suddenly and somewhat unpredictably coming to a catastrophic failure as hollow-core things will. Think of a straw versus, well, pretty much anything else that bends. Most other things aren’t destroyed if they bend slightly into plastic deformation, but a hollow structure almost certainly will be. Solid-core allows you to actually use that region near the buckling force much more safely, which may be yet another reason why the birds they checked with hollow-core feathers are effectively staying well away from it. When you can safely bend, which hollow-core structures are quite bad at, it has major aerodynamic consequences, and should reduces the peak force on the feathers significantly.

Oh, wow, went on a lot longer than I’d intended to. Long story short:
-They probably had solid-core feathers, which is interesting and likely primitive to birds
-This means they were not the most spectacular fliers, but doesn’t tell us much past that
-Behavioral and environmental factors for the test birds weight the comparison toward a relative appearance of weakness for the ancient birds

These birds likely weren’t the equal of some of today’s highest-performance fliers, but you don’t have to be a “poor” flier to fall out of that category.

]]>By: Tkhttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7543
Fri, 14 May 2010 05:46:22 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7543dear Ed, the “more on” links are missing “notrocketscience/”
]]>By: davidhttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7542
Thu, 13 May 2010 23:22:06 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7542I don’t want to believe this, and we all know how that goes. I’m waiting for someone to disprove it. In the meantime I’m thinking there could have been cross-braces inside the feather stems (rachi), or marrow. And powered, sustainable flight is a problematic concept. A chicken is a bird I know, and it flies up to low branches to roost or to get away from predators. It is said the chicken is too heavy to fly. Not sure about that, may be other reasons. Wild turkeys can fly quite well but they don’t migrate. Then, there are other ways to fly on wings than bird flight motion, moth or beetle for example. My bias tells me to wait. Meanwhile it’s a nice paper and apparently summarized well.

I didn’t want to change Brontosaurus, nor Pluto’s status either.

]]>By: David Fulkhttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7541
Thu, 13 May 2010 22:43:42 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7541Ed, I really appreciate your website. I love science but just don’t have the knowledge to really understand it. Thanks for making all this accessible.
]]>By: Ed Yonghttp://blogs.discovermagazine.com/notrocketscience/2010/05/13/first-birds-were-poor-fliers-flaps-would-have-broken-archaeopteryx-feathers/#comment-7540
Thu, 13 May 2010 22:06:26 +0000http://blogs.discovermagazine.com/notrocketscience/?p=1602#comment-7540Zach, paper only came out today
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